The C.I.A. is investigating an informant’s accusation that Iraq obtained a particularly virulent strain of smallpox from a Russian scientist who worked in a smallpox lab in Moscow during Soviet times, senior American officials and foreign scientists say.

The officials said several American scientists were told in August that Iraq might have obtained the mysterious strain from Nelja N. Maltseva, a virologist who worked for more than 30 years at the Research Institute for Viral Preparations in Moscow before her death two years ago.

Miller’s Tuesday scoop in the Times, “C.I.A. Hunts Iraq Tie to Soviet Smallpox,” explores the theory that a Russian virologist named Nelja N. Maltseva might have given “a particularly virulent strain of smallpox” to the Iraqis, a finding that obviously grows out of the expertise she acquired in writing the book.

As the U.N. and member governments seek to uncover whatever illicit weapons programs Iraq might have, few tasks are as urgent as determining whether Baghdad has obtained the smallpox virus.

The only declared reserves of the 120 known strains of smallpox are in two labs, in the U.S. and Russia, but fears that Iraq may possess the virus have lately come to a head.

Why the suspicions? As the New York Times first reported last week, the CIA is investigating the possibility that a Russian scientist, Nelli Maltseva, ferried a nasty strain of smallpox from the Research Institute for Viral Preparations in Moscow to Iraq in 1990. She died two years ago.

A Bush administration intelligence review has concluded that four nations — including Iraq and North Korea — possess covert stocks of the smallpox pathogen, according to two officials who received classified briefings.

. . . In public, the White House has described its smallpox concerns in only hypothetical terms, and until now the gravity of its assessment has not been known.

. . . “Al Qaeda is interested in acquiring biological weapons, to include smallpox,” according to a classified intelligence summary prepared for senior officials debating options on the scope of a preventive vaccination campaign. . . . The “top five list” for al Qaeda, one official said, included anthrax, the nerve agent ricin, and botulinum toxin.

Think about how much money was involved with that war. Completely unaccountable money, pallets of money, shrink-wrapped bundles of cash, literally flowing to all those campaign contributors…